Originally Posted by matt g
Read your owner's manual.
Though I have a 12 gauge, it should be similar for you. I can't be responsible for what you do with YOUR gun, but I use both size shells in my 870 and my Browning and use buckshot in my 870 and in my 1100 (I haven't had the need to shoot buckshot in the browning yet, but wouldn't feel bad doing so). No problems so far...